Recovering Refrigerant from Existing System
1DISCONNECT POWER
Disconnect all power to the existing outdoor unit at the disconnect switch and/or main fuse box/breaker panel.
MAIN FUSE
BOX/BREAKER
PANEL
DISCONNECT
SWITCH
2CONNECT MANIFOLD GAUGE SET Connect a manifold gauge set, clean recovery cylinder and a recovery machine to the service ports of the existing unit.
NOTE recovery machine instructions to make the correct manifold gauge set connections for recovery refrigerant. The illustration below is a typical connection.
MANIFOLD GAUGES
RECOVERY MACHINE
LOW 
HIGH
3RECOVERING REFRIGERANT
CLEAN RECOVERY | OUTDOOR UNIT |
CYLINDER |
|
Remove existing HCFC−22 refrigerant using one of the following procedures:
METHOD 1:
METHOD 2 LIMITATIONS
Use Method 1 if the existing outdoor unit is not equipped with shut−off valves, or if the unit is not operational and you plan to use the existing HCFC−22 to flush the system.
Recover all HCFC−22 refrigerant from the existing system using a recovery machine and clean recovery cylinder. Check gauges after shutdown to confirm that the entire system is completely void of refrigerant.
METHOD 2:
Use Method 2 if the existing outdoor unit is equipped with manual shut−off valves, and you plan to use new HCFC−22 refrigerant to flush the system.
Perform the following task:
AStart the existing HCFC−22 system in the cooling mode and close the liquid line valve.
BUse the compressor to pump as much of the existing HCFC−22 refrigerant into the outdoor unit until the outdoor system is full. Turn the outdoor unit main power OFF and use a recovery machine to remove the remaining refrigerant from the system.
NOTE
ensure complete refrigerant evacuation.
CWhen the low side system pressures reach 0 psig, close the vapor line valve.
DCheck gauges after shutdown to confirm that the valves are not allowing refrigerant to flow back into the low side of the system.
NOTEMethod 2, the listed devices below could prevent full system charge recovery into the outdoor unit:
SOutdoor unit’s high or low−pressure switches (if applicable) when tripped can cycle the compressor OFF.
SCompressor can stop pumping due to tripped internal pressure relief valve.
SCompressor has internal vacuum protection that is designed to unload the scrolls (compressor stops pumping) when the pressure ratio meets a certain value or when the suction pressure is as high as 20 psig. (Compressor suction pressures should never be allowed to go into a vacuum. Prolonged operation at low suction pressures will result in overheating of the scrolls and permanent damage to the scroll tips, drive bearings and internal seals.)
Once the compressor can not pump down to a lower pressure due to any of the above mentioned system conditions, shut off the vapor valve. Turn OFF the main power to unit and use a recovery machine to recover any refrigerant left in the indoor coil and line set.
Figure 4. Refrigerant Recovery
IMPORTANT
The Environmental Protection Agency (EPA) prohibits the intentional venting of HFC refrigerants during maintenance, service, repair and disposal of appliance. Approved methods of recovery, recycling or reclaiming must be followed.
WARNING
Refrigerant can be harmful if it is inhaled. Refrigerant must be used and recovered responsibly.
Failure to follow this warning may result in personal injury or death.
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